Supply chain networks are excessively large and complex at times, and therefore, analyzing their resilience becomes an important concern. We explore this question with respect to a small or medium enterprise (SME), which is cash-constrained. For the analysis, we design a digital twin to continually observe and enhance the performance of the supply chain network. We explicitly model the inventory flow and cash flow details using the system dynamics method. The inventory ordering policies are designed for the SME such that: (i) the enterprise has a non-negative balance at all times, and (ii) a stock-out situation is avoided. Interestingly, we incorporate the business plan, designed using the tacit knowledge of the SME, while deciding the order releases. We validate the model via exhaustive simulation for scenarios with delays in delivery and random shocks to the anticipated demand. In all scenarios, the designed policies are robust against such disruptions to a large extent. Further, we highlight the significance of including a business plan in our digital twin to design a resilient supply chain.